class_docstr: Parse string of one line in annotation file to dict format.
  
  Args:
      keys (list[str]): Keys in result dict. Defaults to
          ['filename', 'text'].
      keys_idx (list[int]): Value index in sub-string list for each key
          above. Defaults to [0, 1].
      separator (str): Separator to separate string to list of sub-string.
          Defaults to ' '.
code: def __init__(
      self,
      keys: Tuple[str, str] = ["filename", "text"],
      keys_idx: Tuple[int, int] = [0, 1],
      separator: str = " ",
      **kwargs,
  ):
      assert isinstance(keys, list)
      assert isinstance(keys_idx, list)
      assert isinstance(separator, str)
      assert len(keys) > 0
      assert len(keys) == len(keys_idx)
      self.keys = keys
      self.keys_idx = keys_idx
      self.separator = separator
      self.strip_cls = StringStripper(**kwargs)
  
file_path: mmocr/mmocr/utils/parsers.py
imports: import json
  import warnings
  from typing import Dict, Tuple
  from mmocr.registry import TASK_UTILS
  from mmocr.utils.string_utils import StringStripper
label_desc: Use image node_id 1 to create a new LineStrParser object  with example: obj = LineStrParser(keys, keys_idx, separator)